Method of forming internal and crown gears



March 1, '1932. SE 1,847,926

METHOD OF FORMING INTERNAL AND CROWN GEARS Fi led Feb. 28, 1929 s Sheets-Sheet i j zic. /1l Z560 3 i 7 w ATTORNEY March 1, 1932. I c, CHASE 1,847,926

METHOD OF FORMING INTERNAL AND CROWN GEARS F iled Feb. 28, 1929 3 Sheets-Sheet 2 C(3- jrl-caz .12 7

MI I g 1 lllll J5 INVENTOR i 6% March I, 1932. r G. c. CHASE"- 1,847,926

METHOD OF FORMING INTERNAL AND CROWN GEARS Filed Feb. 23, 1929 3Sheets-Sheet 5 jzza 10.

' ATTORNEY v Patented Mar. 1, 1932 I 1.84am

UNITED s'r rssl A ENr or'rice GEORGE C. CHASE, OF SOUTH ORANGE, NEW JERSEY, ASSIGNOR TO MONROECALGULAT- ING MACHINE COMPANY, OF ORANGE, NEW JERSEY, A CORPORATION OF DELAWARE METHOD or romaine INTERNAL AND cnown ems Application filed February 28, 1929. Serial No. 343,496.

This invention relates to a method of produclng lnternal gears and crown gears from sheet metal, and the principal object is to devise a method wherebythe' teeth may be confined during the forming operations so as to insure proper pitch relation of the teeth.

Another object is to devise a method of producing substantially finished gears of this Fig. 4 is a face view of the blank as shown in Fig. 3.

Fig. 5 is a perspective View of an internal gear produced by the present method and showing its finished form.

Fig. 6 is a fragmentary view showing the mannerin which an internal gear of the type shown in Fig. 5 and having partial depth teeth would mesh with a pinion.

Fig 7. is an enlarged fragmentary perspective view showing a portion of a finished gear formed with partial depth teeth.

Fig. 8 is a fragmentary sectional view of the same.

Fig. 9 is a fragmentary face view of the same.

Fig. 10 is a view similar to Fig. 7, but show- .ing full depth teeth.

Fig. 11 is a view partly in section showing the punch and die for drawing and finishing an internal gear.

Fig. 12 is a fragmentary view of the punch for use in the tool shown in Fig. 11. I

Fig. 13 is a bottom plan view of the same.

Fig. 14' is a view. showing the manner of constructing the punch. i

Fig. 15 shows a blank for making a crown gear.

Fig. 16 shows in section the blank of Fig. 16 drawn up.

Fig. 17 is a face-view of the same.

Fig. 18 shows the punch and die utilized for finishing the crown gear, and i Fig. 19 is an enlarged fragmentary perspective View of a portion of the finished crown gear.

Like characters of reference refer to like parts in all views.

Generally speaking, this invention contemplates a method of forming internal and crown gears by firststriking out or otherwise 1 forming a blank, then swaging the teeth of this blank to nearly their finished form, and then drawing up-the toothed edge of the blank and finishing the teeth, the teeth being confined during all operations so as to preserve proper relationship of the teeth.

Referring to the drawings in detail and in particular to Figs. 1 to 14 inclusive, 30.rep-

resents a blank which may be formed from or by milling.

The blank shown in Figs. 1 and 2 has been formed by punching and it will be noted that the teeth 31 are somewhat rounded as at 32. This is because this face of the blank was to- .ward the die in the blanking operation, it

sheet metal either by a punching operation are left a trifle larger than their finished size. The round at 32 has been taken advantage of' as a start towards the forming of the teeth, the blanks being placed in the die with this side towards the swaging punch. The shaping of the teeth as in this second op eration may be accomplished in various ways, but the preferred manner is by crushing the teeth to shape by the use of a swaging punch that would form all the teeth simu1- taneously, thereby confining all the teeth during the swaging operation and preserving them in proper relationship to each other. If the round at 32 is sufficiently pronounced, then the swaging operation illustrated in Figs. 3 and 4 might be omitted and the blank passed directly to the finishing tool.

After the blank has been formed to the shape shown in Figs. 3 and 4, the same is passed through a drawing and finishing die illustrated in Fig. 11, and in which the .edge of the blank 30 is drawn up as at 33, Fig. 5, and the teeth 31 are given their finished form.

Referring now particularly to Figs. 11, 12 and 13, 34 represents a die, and. 35 a punch for drawing up and finishing the gear to the form shown in Fig. 5. The die 34 is provided with an ejector 36, having co-operat-ing;

springs 37 and a pilot 38. Secured to the face of the die 34 is a set edge 39, by means of which the blank is properly positioned prior to depression of the punch 35. The punch is formed with the usual pilot 40 and may be provided with spring ejector pins (not shown).

Inasmuch as an internal gear has several teeth in mesh simultaneously with its correlated pinion, it is not necessary that the teeth should be full depth. The punch 35 shown in Fig. 11 is constructed for forming partial depth teeth and it is, therefore, necessary that the teeth formed in the punch should be of the proper shape and depth to entirely confine the teeth of the gear which is being formed and to insure maintaining the proper pitch line. In order to do this the cutter used in cutting the teeth on the punch 35 must be modified from standard design and for this purpose, I take a standard cutter and grind off the ends of the teeth.

. In Fig. 14 the punch 35 is indicated, the form of the same being shown in full line, and dotted lines indicating the form which the teeth would have taken if full depth teeth were desired on the finished gear. The pitch line is indicated at 43. 7

After the gear has been formed by themaction of the die 34 and punch 35, as indicated in Fig. 11, the ends of the teeth could be struck bya stripper punch (not shown) in a double acting press, or in a separate finishing die so as'to finish the teethas to length and to cause the teeth of the gear to more. closely fill the teeth of'the punch. It is desired to particularly emphasize the fact that the teeth of the gear are confined and consequently are forced into proper relationship with each other so that when the gear is removed from the die 34 it is in finished condition.

While not usually required, in internal gears, the teeth may be made full depth, al-

gear would preferably be made with partial depth teeth.

In forming crown gears by this method a blank is first obtained in any desired manner so as to have teeth of the finished shape, but a little larger in size, this blank being shown in Fig. 15 and indicated at 44, the teeth being indicated at 45. The gear is then placed in a forming die and bent up to the proper shape as shown in Figs. 16 and 17 This formed blank is then placed in a die 46, shown in Fig. 1 8, and is struck by a unch 47 having the finished form of gear teetli cut in it. The

- teeth are thus crushed to their proper shape -piece of tool steel, then hardening this master and sinking it into the soft punchswaging tool so as to give the latter the desired shape. The punch is then hardened and will reproduce its shape in the gear blank when forced Into the same. The blank 44 having been formed with teeth 45 of substantially the finished shape and size, the punch 47 should have very little work to do other than truing up the shape andsize of the teeth.

While I. have described what I consider to be the best manner of carrying my invention into efi'ect, it is obvious that some slight changes in the specific method described might be indulged in without departing from the spirit of the invention, and I, therefore, do not limit my invention to the precise features described.

What I claim is:

The method of forming gears which conportion of the teeth formed from the edge of the blank.

I In testimony whereof I aflix my si ature.

' GEORGE C. 0 SE. 

